Linear compressor

ABSTRACT

Disclosed herein is a linear compressor. In the present invention, an initial value control nut for controlling an initial position of a piston and a releasing protection nut for preventing the initial value control nut from releasing are combined in a bolt of a stator cover as a double nut method. The initial value control nut and the releasing protection nut are wound in the opposite direction. Therefore, it can prevent the initial value control nut from releasing, and can prevent the linear compressor from breaking down, thus improving the durability and the reliability.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a linear compressor, more particularly, wherein an initial value control nut is prevented from releasing, which controls an initial position of a piston. Thus, the linear compressor has an effect on improving the durability and the reliability.

2. Description of the Related Art

Generally, a linear compressor is a machine to inhale, to compress, and to discharge fluid by linearly reciprocating a piston within a cylinder, by device of linear driving force of a linear motor.

FIG. 1 shows the linear compressor, in accordance with the prior art.

The conventional linear compressor comprises a hermetic casing 2, and a linear compression part positioned in the hermetic casing 2 to compress fluid(see FIG. 1).

An inlet 3 for inhaling fluid penetrates one end of the hermetic casing 2, and a linear compression part is held by a main damper 4 and a subsidiary damper 5 set in the hermetic casing 2, so as to absorb a shock.

The linear compression part includes a cylinder block 7 having the cylinder 6, a back cover 9 provided with an inhale pipe 8, the piston 10 which moves back and forth within the cylinder 6, the linear motor 20 which drives the piston 10, and an exhale part 30 placed in a front of the cylinder 6 to discharge fluid compressed in the cylinder 6.

The exhale part 30 is connected to an exhale pipe 31 which guides fluid drained from the cylinder to the outside of the hermetic casing.

The linear motor 20 is divided by a stationary part and a movable part. The stationary part includes an outer stator 21, an inner stator 22, and a coil 23 with a magnetic field. The movable part includes a magnet 24 that linearly reciprocates by magnetic force around the coil 23, and a magnet frame 25 which the magnet 14 is fastened to.

The cylinder block 7 is located in a front of the outer stator 21, and a stator cover 26 is set in its rear.

The piston 10 receives linear driving force from the magnet 24, and linearly reciprocates within the cylinder 6. It is in the shape of a cylinder, which is open at its rear. An inhale passage where fluid is entered is provided therein. A flange 11 is provided in its rear, so as to be fastened to the magnet frame 25.

In a rear of the magnet frame 25, a spring supporting member 27 is placed to gear with the magnet frame 25. The spring supporting member 27 has a main spring for elastically supporting linear reciprocation of the piston 10.

The spring supporting member 27 is disposed between the stator cover 26 and the back cover 9, being fastened to the magnet frame 25. The main spring includes a 1^(st) main spring 28 between the spring supporting member 27 and the back cover 9, and a 2^(nd) main spring 29 between the spring supporting member 27 and the stator cover 26.

A bolt 32 protruded toward the back cover 9 is equipped in the stator cover 26, so as to penetrate the spring supporting member 27 and the back cover 9.

The spring supporting member 27 and the back cover 9 respectively have a through hole to make the bolt 32 penetrate. After the bolt 32 penetrates the spring supporting member 27 and the back cover 9, it is combined with an initial value control nut 33 in a rear of the back cover 9, which controls an initial position of the piston 10.

The conventional linear compressor with the above construction operates in the following sequence.

In operation of the linear motor 20, the magnet 24 linearly reciprocates, its linear driving force is delivered to the piston 10 through the magnet frame 25. The piston 10 moves back and forth within the cylinder 6.

When the piston 10 linearly reciprocates within the cylinder 6, fluid within the hermetic casing 2 is inhaled into the inhale pipe 8 of the back cover 9, is compressed in the cylinder 6 by the piston 10, and is discharged to the outside of the hermetic casing 2 through the exhale part 30 and the exhale pipe 31.

The piston 10 is supported by the 1^(st) main spring 28 and the 2^(nd) main spring 29, when the piston 10 moves back and forth.

When the piston 10 is assembled to move back and forth within the cylinder 6, the piston 10 should occupy its initial position appropriately. The initial position of the piston 10 is controlled, after inserting the spring supporting member 27, the 1^(st) main spring 28 and the back cover 9, in regular order, into the bolt 32, and combining with the initial value control nut 33 in the rear of the back cover 9.

The back cover 9 pushes the 1^(st) main spring 28, depending on an extent that the initial value control nut 33 is wound. As the spring supporting member 27 is transferred by the elasticity of the 1^(st) main spring 28, the position of the piston 10 combined with the spring supporting member 27 is controlled.

However, in the conventional linear compressor, the initial value control nut 33 is easily released by a vibration and the shock. When the initial value control nut 33 becomes released, the piston 10 changes its initial position, resulting in influencing on compressibility. Furthermore, a separation of the initial value control nut 33 brings a mishap to the linear compressor.

In order to prevent the initial value control nut 33 from releasing, the initial value control nut 33 is combined with the bolt 32, and is fixed by welding 34. In that case, a restriction still remains that the initial value control nut 33 comes to released, caused by the trouble in welding.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the present invention to provide a linear compressor, wherein an initial value control nut for controlling an initial position of a piston is not released, so that the initial position of the piston is not changed, thereby enhancing not only compressibility but also the durability and the reliability.

The foregoing and other aspects are achieved by providing the linear compressor, based on the present invention, which comprises a stator cover fastened to a linear motor, a back cover positioned at a regular interval from the stator cover, the piston which linearly reciprocates by the linear motor, a spring supporting member mounted between the stator cover and the back cover, so as to gear with the piston, a main spring mounted between the spring supporting member and the back cover to elastically hold linear reciprocation of the piston, a connection device equipped in the stator cover to penetrate the spring supporting member and the back cover, an initial value control device combined with the connection device in a back of the back cover, so as to control the initial position of the piston, and a releasing protection device combined with the connection device, so as to prevent the initial value control device from releasing.

The connection device is protruded in the stator cover toward the back cover, which is a bolt having a screw thread. The initial value control device is the initial value control nut combined with the bolt. The releasing protection device is a releasing protection nut combined with the bolt which is combined with the initial value control nut.

Either the initial value control nut or the releasing protection nut is a right screw and the rest is a left screw.

The bolt includes a rod which penetrates the spring supporting member, a main screw prolonged from the rod and provided with the screw thread to combine with the initial value control nut, and a subsidiary screw prolonged from the main screw and provided with the screw thread to combine with the releasing protection nut.

The main screw and the subsidiary screw have a different diameter.

According to an aspect of the present invention, the linear compressor comprises the stator cover fastened to the linear motor, the back cover positioned at a regular interval from the stator cover, the piston which linearly reciprocates by the linear motor, the spring supporting member mounted between the stator cover and the back cover, so as to gear with the piston, the main spring mounted between the spring supporting member and the back cover to elastically hold linear reciprocation of the piston, the connection device equipped in the stator cover to penetrate the spring supporting member and the back cover, the initial value control device combined with the connection device between the main spring and the back cover, so as to control the initial position of the piston, and a fixing device which allows the connection device and the back cover to be fastened to each other in the back of the back cover.

The connection device is protruded in the stator cover toward the back cover, which is the bolt having the screw thread. The fixing device is a lock nut combined with the bolt in the back of the back cover.

The initial value control device is the initial value control nut combined with the bolt, between the main spring and a front of the back cover.

The initial value control nut includes a connection portion combined with the bolt, and a sheet portion radially protruded in the connection portion to support the main spring.

According to an aspect of the present invention, the linear compressor comprises the stator cover fastened to the linear motor, the back cover positioned at a regular interval from the stator cover, the piston which linearly reciprocates by the linear motor, the spring supporting member mounted between the stator cover and the back cover, so as to gear with the piston, the main spring mounted between the spring supporting member and the back cover to elastically hold linear reciprocation of the piston, the bolt equipped in the stator cover to penetrate the spring supporting member and the back cover, the main nut positioned in the main spring to be combined with the bolt, and the subsidiary nut combined with the bolt in the back of the back cover.

In the linear compressor of the present invention having the above-mentioned construction, the initial value control nut which controls the initial position of the piston and the releasing protection nut which prevents the initial value control nut from releasing are combined in the bolt of the stator cover as a double nut method, so that it is capable of preventing the initial value control nut from releasing, and of preventing the linear compressor from being out of order. Thus, the durability and the reliability of the linear compressor are enhanced.

As either the initial value control nut or the releasing protection nut is the right screw, and the rest is the left screw, the initial value control nut and the releasing protection nut are wound in the opposite direction, thus enlarging an effect of preventing the initial value control nut from releasing.

An inside diameter of the releasing protection nut is smaller than that of the initial value control nut, thus enlarging the effect of preventing the initial value control nut from releasing.

The linear compressor of the present invention having the above-mentioned construction comprises the initial value control nut which controls the initial position of the piston between the main spring and the back cover, and the lock nut fastened to the bolt of the stator cover and the back cover in the back of the back cover. The initial value control nut and the lock nut are combined as the double nut method, therefore it prevents the initial value control nut from releasing, and enhances the durability and the reliability.

After the initial position of the piston is adjusted by the initial value control nut, the back cover is installed in the bolt by the nut. Hereby, an installation of the back cover becomes easy.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of the present invention will become apparent and more readily appreciated from the following description of the embodiments of the invention, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a sectional view of a linear compressor, according to the prior art;

FIG. 2 is a sectional view of the linear compressor, according to a 1^(st) embodiment of the present invention;

FIG. 3 is a lateral view of an initial value control device and a releasing protection device, according to the 1^(st) embodiment of the present invention;

FIG. 4 is an enlarged sectional view of the initial value control device and the releasing protection device, according to the 1^(st) embodiment of the present invention;

FIG. 5 is a lateral view of a connection device, according to the 1^(st) embodiment of the present invention;

FIG. 6 is a lateral view of the initial value control device and a fixing device of the linear compressor, according to a 2^(nd) embodiment of the present invention;

FIG. 7 is an enlarged sectional view of the initial value control device and the fixing device, according to the 2^(nd) embodiment of the present invention;

FIG. 8 is a lateral view of the initial value control device and the fixing device of the linear compressor, according to a 3^(rd) embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.

FIG. 2 shows a linear compressor, according to a 1^(st) embodiment of the present invention, FIGS. 3 and 4 show an initial value control device and a releasing protection device, according to the 1^(st) embodiment of the present invention, and FIG. 5 shows a connection device, according to the 1^(st) embodiment of the present invention.

As referring to FIGS. 2 to 5, the linear compressor, in accordance with the 1^(st) embodiment of the present invention comprises a hermetic casing 50, and a linear compression part positioned in the hermetic casing 50 to compress fluid.

One end of the hermetic casing 50, an inlet 51 for inhaling fluid is installed through. The linear compression part is suspended by a main damper 52 and a subsidiary damper 53 in the hermetic casing 50, so as to absorb a shock.

The linear compression part includes a cylinder block 55 provided with a cylinder 54, a back cover 57 provided with an inhale pipe 56 facing the inlet 51, a piston 58 which moves back and forth in the cylinder 54, a linear motor 60 which generates driving force to make the piston 58 linearly reciprocate, and an exhale part positioned in a front of the cylinder 54, so as to discharge fluid compressed in the cylinder 54.

The linear motor 60 is divided by a stationary part and a movable part. The stationary part includes an outer stator 61, an inner stator 62, and a coil 63 with a magnetic field. The movable part includes a magnet 64 which linearly reciprocates by magnetic force around the coil 63, and a magnetic frame 65 fastened to the magnet 64.

The piston 58 is fastened to the magnet frame 65, in order to deliver linear driving force of the magnet 64 to the piston 58. One end of the piston 58 is inserted into the cylinder 54, and the other is fastened to the magnet frame 65.

The piston 58 is in the shape of a cylinder, which is open at its rear. An inhale passage 59 where fluid is entered is provided therein. A flange 66 is provided in its rear, so as to be fastened to a front of the magnet frame 65.

In a front of the piston 58, an inhale port 67 for making fluid inhale into a compression chamber of the cylinder 54 is formed, and an inhale valve 68 for opening and closing the inhale port 67 is installed.

The exhale part includes an inner exhale cover 70 fastened to the cylinder block 55 and provided with an exhale hole, an exhale valve 71 supported in the inner exhale cover 70 by a spring to open and close the compression chamber of the cylinder 54, and an outer exhale cover 72 positioned at a regular interval from the outside of the inner exhale cover 70. An exhale pipe 73 is connected to the outer exhale cover 72, which guides fluid drained from the cylinder 54 to the outside of the hermetic casing 50.

A muffler 74 for reducing a noise is installed between a rear of the piston 58 and the inhale pipe 56 of the back cover 57. The muffler 74 includes a muffler body 75 placed in the rear of the piston 58, and an entry pipe 76 prolonged from the muffler body to be inserted into the piston 58.

The cylinder block 55 is located in a front of the outer stator 61, and a stator cover 77 for covering the outer stator 61 is set in a rear of the outer stator 61. The back cover 57 is spaced apart from the stator cover 77 by predetermined distance.

A spring supporting member 78 is installed between the stator cover 77 and the back cover 57, in order to gear with the piston 58 and the magnet frame 65. The spring supporting member 78 is combined with a back of the magnet frame 65.

The spring supporting member 78 has a main spring to elastically hold linear reciprocation of the piston 58.

The main spring includes a 1^(st) main spring 80 arranged between the spring supporting member 78 and the back cover 57, and a 2^(nd) main spring 81 arranged between the spring supporting member 78 and the stator cover 77. The 1^(st) main spring 80 is disposed in upper and lower sides of the hermetic casing 50, while the 2^(nd) main spring 81 is disposed in right and left sides of the hermetic casing 50.

The connection device is equipped in the stator cover 77, which penetrates the spring supporting member 78 and the back cover 57, and allows the stator cover 77 to combine with the spring supporting member 78 and the back cover 57.

One end of the connection device is fastened to the stator cover 77, and the other is protruded toward the back cover 57, which is a bolt 82 having a screw thread in its circumference.

A through hole is formed in the spring supporting member 78, where the bolt 82 is penetrated, so as to slide a front and rear direction in the bolt 82 by gearing with the piston 58, when the piston 58 moves back and forth.

In a rear of the back cover 57, there are the initial value control device combined with the bolt 82 for controlling an initial position of the piston 58, and the releasing protection device combined with the bolt 82 for preventing the initial value control device from releasing.

The initial value control device is an initial value control nut 83 combined with the bolt 82, and the releasing protection device is a releasing protection nut 84 combined with the bolt 82 which is combined with the initial value control nut 83.

As shown in FIG. 5, either the initial value control nut 83 or the releasing protection nut 84 is a right screw, and the rest is a left screw. An example that the initial value control nut 83 is the right screw that is combined in a right direction in rotating, and the releasing protection nut 84 is the left screw that is combined in a left direction in rotating is described below.

The bolt 82 includes a rod 85 which penetrates the spring supporting member 78, a main screw 86 prolonged from the rod 85 and provided with the screw thread, so as to combine with the initial value control nut 83, and a subsidiary screw 87 prolonged from the main screw 86 and provided with the screw thread, so as to combine with the releasing protection nut 84.

The main screw 86 has the screw thread to be wound in the right direction, and the subsidiary screw 87 has the screw thread to be wound in the left direction.

As shown in FIG. 5, the main screw 86 and the subsidiary screw 87 have a different diameter. The diameter of the subsidiary screw 87 is desirable to be smaller than that of the main screw 86.

An inside diameter of the initial value control nut and the releasing protection nut 84 are respectively faced to an outside diameter of the main screw 86 and the subsidiary screw 87.

A process of the linear compressor, according to the 1^(st) embodiment of the present invention is described in the following.

When the linear motor 60 is in operation, the magnet 64 linearly reciprocates, and its linear motion is transmitted to the piston 58 through the magnet frame 65. The piston 58 linearly reciprocates within the cylinder 54.

When the piston 58 linearly reciprocates within the cylinder 54, fluid in the hermetic casing 50 is inhaled into the inhale pipe 56 of the back cover 57, is compressed in the cylinder 54 by the piston 58, and is discharged to the outside of the hermetic casing 50 through the inner and the outer exhale cover 70, 72 and the exhale pipe 73.

When the piston 58 moves backward, the spring supporting member 78 moves backward together with the piston 58, and the 1^(st) main spring 80 becomes compressed. When the piston 58 moves forward, the spring supporting member 78 moves forward, and the 2^(nd) main spring 81 becomes compressed.

Linear reciprocation of the piston 58 is elastically held by the elasticity of the 1^(st) and the 2^(nd) main spring 80, 81.

A method of adjusting the initial position of the piston 58 is as follows.

After the spring supporting member 78, the 1^(st) main spring 80 and the back cover 57, in regular order, are inserted into the bolt 82 fastened to the stator cover 77, the initial value control nut 83 is combined with the main screw 86 of the bolt 82 in the rear of the back cover 57.

As the initial value control nut 83 is combined with the main screw 86 of the bolt 82, the initial value control nut 83 pushes the 1^(st) main spring 80 through the back cover 57.

While the spring supporting member 78 combined to gear with the piston 58 is moved by the elasticity of the 1^(st) main spring 80, the initial position of the piston 58 is decided.

According to an extent that the initial value control nut 83 is combined with the bolt 82, the initial position of the piston 58 is controlled.

After the initial position of the piston 58 is adjusted, the releasing protection nut 84 is combined with the subsidiary screw 87 of the bolt 82.

The initial value control nut 83 and the releasing protection nut 84 are combined in the bolt 82 as a double nut method, and the initial value control nut 83 and the releasing protection nut 84 are wound in the opposite direction. Thus, it can prevent the initial value control nut 83 from releasing.

In describing a 2^(nd) embodiment of the present invention, the identical reference number is conferred upon the same construction with the 1^(st) embodiment of the present invention, referring to FIG. 2, and a detailed explanation is omitted.

FIGS. 6 and 7 show the initial value control device and a fixing device of the linear compressor, according to the 2^(nd) embodiment.

As referring to FIGS. 6 and 7, the linear compressor, according to the 2^(nd) embodiment of the present invention comprises the stator cover 77 fastened to the linear motor 60, the back cover 57 spaced apart from the stator cover 77 by predetermined distance, the piston 58 which linearly reciprocates by the linear motor 60, the spring supporting member 78 installed between the stator cover 77 and the back cover 57, so as to gear with the piston 58, the 1^(st) main spring 80 mounted between the spring supporting member 78 and the back cover 57 to elastically support linear reciprocation of the piston 58, the connection device equipped in the stator cover 77 to penetrate the spring supporting member 78 and the back cover 57, the initial value control device combined with the connection device between the 1^(st) main spring 80 and the back cover 57, so as to control the initial position of the piston 58, and the fixing device which allows the connection device and the back cover 57 to be fastened to each other in the rear of the back cover 57.

The 2^(nd) main spring 81 is further comprised, which elastically holds linear reciprocation of the piston 58, by being installed between the spring supporting member 78 and the stator cover 77.

One end of the connection device is fastened to the stator cover 77, and the other is protruded toward the back cover 57, which is the bolt 90 having the screw thread in its circumference.

The initial value control device is the initial value control nut 93 combined with the bolt 90, between the 1^(st) main spring 80 and a front of the back cover 57.

The initial value control nut 93 includes a connection portion 94 having the screw thread in its circumference, so as to combine the bolt 90, and a sheet portion 95 radially protruded in the connection portion 94, so as to support the 1^(st) main spring.

The fixing device is a lock nut 96 combined with the bolt 90 which penetrates the back cover 57 in the rear of the back cover 57.

The bolt 90 includes the rod 91 penetrating the spring supporting member 78, a screw 92 prolonged from the rod 91 and provided with the screw thread to combine with the initial value control nut and the lock nut.

The method of adjusting the initial position of the piston in the linear compressor, according to the 2^(nd) embodiment of the present invention is as follows.

After the spring supporting member 78 and the 1^(st) main spring 80, in regular order, are inserted into the bolt 90 fastened to the stator cover 77, the initial value control nut 93 is combined with the bolt 90.

As the initial value control nut 93 is combined with the bolt 90, the initial value control nut 93 pushes the 1^(st) main spring 80. While the spring supporting member 78 combined to gear with the piston 58 is moved by the elasticity of the 1^(st) main spring 80, the initial position of the piston 58 is decided.

The spring supporting member 78 has a regular interval from the back cover 57 by the initial value control nut 93, the initial position of the piston 58 combined with the spring supporting member 78 is decided.

Thereafter, the back cover 57 is set in the bolt 90, and the lock nut 96 is combined with the bolt 90 in the rear of the back cover 57.

As the initial value control nut 93 and the lock nut 96 are combined in the bolt 90 as the double nut method, it can prevent the initial value control nut 93 from releasing by mutual pushing power between the initial value control nut 93 and the lock nut 96.

Without defining the above embodiment, a spacer may be used for the initial value control device, which allows the spring supporting member 78 to be parted from the back cover 57 by predetermined distance.

In describing a 3^(rd) embodiment of the present invention, the identical reference number is conferred upon the same construction with the 1^(st) embodiment of the present invention, referring to FIG. 2, and a detailed explanation is omitted.

FIG. 8 shows the initial value control device and the fixing device of the linear compressor, according to the 3^(rd) embodiment.

As shown in FIG. 8, the linear compressor, according to the 3^(rd) embodiment of the present invention comprises the stator cover 77 fastened to the linear motor 60, the back cover 57 spaced apart from the stator cover 77 by predetermined distance, the piston 58 which linearly reciprocates by the linear motor 60, the spring supporting member 78 installed between the stator cover 77 and the back cover 57, so as to gear with the piston 58, the 1^(st) main spring 80 mounted between the spring supporting member 78 and the back cover 57 to elastically support linear reciprocation of the piston 58, the connection device equipped in the stator cover 77 to penetrate the spring supporting member 78 and the back cover 57, the initial value control device combined with the connection device and equipped in the 1^(st) main spring 80, so as to control the initial position of the piston 58, and the fixing device which allows the connection device and the back cover 57 to be fastened to each other in the rear of the back cover 57.

The 2^(nd) main spring 81 is further comprised, which elastically holds linear reciprocation of the piston 58, by being installed between the spring supporting member 78 and the stator cover 77.

One end of the connection device is fastened to the stator cover 77, and the other is protruded toward the back cover 57, which is the bolt 100 having the screw thread in its circumference.

The outside diameter of the initial value control device is smaller than the inside diameter of the 1^(st) main spring 80, and the initial value control device is the initial value control nut 103 combined with the bolt 100.

The fixing device is the lock nut 104 combined with the bolt 100 in the rear of the back cover 57.

The bolt 100 includes the rod 101 penetrating the spring supporting member 78, the screw 102 prolonged from the rod 101 and provided with the screw thread to be combined with the initial value control nut 103 and the lock nut 104.

The method of adjusting the initial position of the piston in the linear compressor, according to the 3^(rd) embodiment of the present invention is as follows.

After the spring supporting member 78 and the 1^(st) main spring 80, in regular order, are inserted into the bolt 100 fastened to the stator cover 77, the initial value control nut 103 is combined with the bolt 100.

When the back cover 57 is inserted into the bolt 100 combined with the initial value control nut 103, the 1^(st) main spring is supported by the back cover 57.

An assembling position of the back cover 57 is decided, depending on the extent that the initial value control nut 103 is combined with the bolt 100, and the back cover 57 pushes the 1^(st) main spring 80. The spring supporting member 78 is moved, and the initial position of the piston 58 is decided.

Thereafter, the lock nut 104 is combined with the bolt 100 that penetrates the back cover 57, releasing is protected by mutual pushing power of the initial value control nut 103 and the lock nut 104 in the front and the rear of the back cover 57. Furthermore, an initial position of the back cover 57 is firmly fixed.

The operational effects of the linear compressor, according to the present invention are described in the following.

As apparent from the above description, in the linear compressor of the present invention, the initial value control nut for controlling the initial position of the piston and the releasing protection nut for preventing the initial value control nut from releasing are combined in the bolt of the stator cover as the double nut method, so that it is possible to prevent the initial value control nut from releasing, and to prevent the linear compressor from breaking down, thereby enhancing the durability and the reliability.

As apparent from the above description, either the initial value control nut or the releasing protection nut is the right screw, and the rest is the left screw. Furthermore, the initial value control nut and the releasing protection nut are wound in the opposite direction, resulting in enlarging an effect of preventing the initial value control nut from releasing.

As apparent from the above description, the inside diameter of the initial value control nut is smaller than that of the releasing protection nut, resulting in enlarging the effect of preventing the initial value control nut from releasing.

As apparent from the above description, the linear compressor, in accordance with the present invention comprises the initial value control nut for controlling the initial position of the piston between the main spring and the back cover, and the lock nut for fastening the bolt of the stator cover and the back cover in the rear of the back cover, the initial value control nut and the lock nut are combined as the double nut method. With this configuration, it can prevent the initial value control nut from releasing, and can prevent the linear compressor from breaking down, thus improving the durability and the reliability.

As apparent from the above description, the back cover is mounted in the bolt by the nut, after the initial position of the piston is adjusted by the initial value control nut. The back cover can be easily installed.

Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

The present disclosure relates to subject matter contained in Korean Application Nos. 10-2004-0081694, filed on Oct. 13, 2004, and 10-2004-0088791, filed on Nov. 3, 2004, the contents of which are herein expressly incorporated by reference in their entireties. 

1. A linear compressor comprising: a stator cover fastened to a linear motor; a back cover spaced apart from the stator cover by predetermined distance; a piston which linearly reciprocates by the linear motor; a spring supporting member installed between the stator cover and the back cover, so as to gear with the piston; a main spring mounted between the spring supporting member and the back cover to elastically hold linear reciprocation of the piston; a connection device equipped in the stator cover to penetrate the spring supporting member and the back cover; an initial value control device combined with the connection device in a rear of the back cover, so as to control an initial position of the piston; and a releasing protection device combined with the connection device, so as to prevent the initial value control device from releasing.
 2. The linear compressor as set forth in claim 1, wherein the connection device is a bolt protruded in the stator cover toward the back cover and provided with a screw thread.
 3. The linear compressor as set forth in claim 2, wherein the initial value control device is an initial value control nut combined with the bolt by screwing.
 4. The linear compressor as set forth in claim 3, wherein the releasing protection device is a releasing protection nut combined with the bolt by screwing, said bolt being combined with the initial value control nut.
 5. The linear compressor as set forth in claim 4, wherein either the initial value control nut or the releasing protection nut is a right screw, and the rest is a left screw.
 6. The linear compressor as set forth in claim 4, wherein the bolt includes a rod penetrating the spring supporting member, a main screw prolonged from the rod and provided with the screw thread to combine with the initial value control nut, and a subsidiary screw prolonged from the main screw and provided with the screw thread to combine with the releasing protection nut.
 7. The linear compressor as set forth in claim 6, wherein the main screw and the subsidiary screw have a different diameter.
 8. The linear compressor as set forth in claim 7, wherein the main spring further includes a spring arranged between the spring supporting member and the stator cover to elastically support linear reciprocation of the piston.
 9. A linear compressor comprising: a stator cover fastened to a linear motor; a back cover spaced apart from the stator cover by predetermined distance; a piston which linearly reciprocates by the linear motor; a spring supporting member installed between the stator cover and the back cover, so as to gear with the piston; a main spring mounted between the spring supporting member and the back cover to elastically hold linear reciprocation of the piston; a connection device equipped in the stator cover to penetrate the spring supporting member and the back cover; an initial value control device combined with the connection device between the main spring and the back cover, so as to control an initial position of the piston; and a fixing device which allows the connection device and the back cover to be fastened to each other in a rear of the back cover.
 10. The linear compressor as set forth in claim 9, wherein the connection device is a bolt protruded in the stator cover toward the back cover and provided with a screw thread.
 11. The linear compressor as set forth in claim 10, wherein the fixing device is a lock nut combined with the bolt in the rear of the back cover.
 12. The linear compressor as set forth in claim 11, wherein the initial value control device is an initial value control nut combined with the bolt by screwing, between the main spring and a front of the back cover.
 13. The linear compressor as set forth in claim 12, wherein the initial value control nut includes a connection portion combined with the bolt, and a sheet portion radially protruded in the connection portion to support the main spring.
 14. The linear compressor as set forth in claim 13, wherein the bolt includes a rod penetrating the spring supporting member, a screw prolonged from the rod and provided with the screw thread to combine with the initial value control nut and the lock nut.
 15. The linear compressor as set forth in claim 14, wherein the main spring further includes a spring arranged between the spring supporting member and the stator cover to elastically support linear reciprocation of the piston.
 16. A linear compressor comprising: a stator cover fastened to a linear motor; a back cover spaced apart from the stator cover by predetermined distance; a piston which linearly reciprocates by the linear motor; a spring supporting member installed between the stator cover and the back cover, so as to gear with the piston; a main spring mounted between the spring supporting member and the back cover to elastically hold linear reciprocation of the piston; a connection device equipped in the stator cover to penetrate the spring supporting member and the back cover; an initial value control device combined with the connection device by being placed in the main spring, so as to control an initial position of the piston; and a fixing device which allows the connection device and the back cover to be fastened to each other in a rear of the back cover.
 17. The linear compressor as set forth in claim 16, wherein the connection device is a bolt protruded in the stator cover toward the back cover and provided with a screw thread.
 18. The linear compressor as set forth in claim 17, wherein an outside diameter of the initial value control device is smaller than an inside diameter of the main spring, said initial value control device being an initial value control nut combined with the bolt by screwing.
 19. The linear compressor as set forth in claim 18, wherein the fixing device is a lock nut combined with the bolt in the rear of the back cover.
 20. The linear compressor as set forth in claim 19, wherein the main spring further includes a spring arranged between the spring supporting member and the stator cover to elastically support linear reciprocation of the piston. 